NOTOMMATAD AI. 39 
thin and blade-like, straight but slightly incurved at the free end, deeply truncate above 
where the rami are jointed, which are long triangular blades arching backwards. The 
mallet are slender rods, each with a process, and an wncus of two fingers.! 
Ehrenberg describes the species as parasitic on the branching Bell-vorticels Hpistylis 
and Carchesium, among whose twigs it lays its eggs; and also in Volvor. I have seen 
it always free, though repeatedly in close association with both these Infusoria. I have 
been acquainted with it from many localities since 1850. It is lively in its motions; 
yet frequently adhering to the glass, and moving by a feeble crawling ; it can, however, 
swim rapidly. Its contractions are almost perpetual, and very vigorous.—P.H.G.] 
Length, when extended, ;+; inch. Habitat. Around London; Walthamstow ; 
Leamington Canal; Cheltenham; Woolston; Birmingham: pools and garden reser- 
voirs (P.H.G.). 
P. parasita, Ehrenberg. 
(Pl. XVIII. fig. 11.) 
Notommata parasita  . ¢ 5 Ehrenberg, Die Infus. 1838, p. 426, Taf. 1. fig. 1. 
Hertwigia volvocicola . 4 : Plate, Jenaisch. Zeits. f. Natur. 1885, p. 26, figs. 7, 8. 
(SP. CH. Body cylindric or gibbous, rounded at each end ; foot and toes wanting. 
Parasitic in Volyox. 
To the characters just given may be added that the jaws are long, slender, protrusile, 
and asymmetric: the mallei being dissimilar in length and curvature; thus recalling 
the Rattulide. A brilliant crimson eye, wart-shaped, sits on the dorsal corner of a 
large occipital brain; from the front of which projects a club-shaped antenna, some- 
times drooping, sometimes erect. The prominent round head is clothed with fine 
cilia, and surrounded by a wreath of stronger vibration; when this is retracted the 
margin is thrown into puckers. 
The habits of this inconspicuous species are curious; for it is parasitic within the 
spheres of Volvox globator. Examining this elegant creature, we may, even with a 
pocket-lens, discern which are tenanted, by a spot differing from the young clusters in 
form and colour. Such a spot proves to be the Proales, snugly ensconced within the 
globe, in whose spacious area it lives at ease, and swims to and fro like a goldfish in a 
glass vase. For the most part it affects the inner surface, engaged in devouring the 
green Monads that stud the gelatinous expanse, or else eating away the embryo clusters. 
Sometimes laid eggs are present, with the Proales ; sometimes eggs alone. The young 
seems always hatched in a Volvoz, and, entering an embryo cluster, is expelled with it. 
Often they eat their way out, and swim atfreedom. Observing in a globe one large egg, 
I opened the globe with a needle, and freed the Proales, placing it in water, and adding 
several Volvoces, all untenanted. But it did not enter one, during several hours’ obser- 
vation. During this period it discharged, loose in the water, an ephippial egg, covered 
with prickles. I have seen a prickly egg and a smooth one, transparent, with eye and 
jaws visible, in the same sphere. One of the latter I saw hatched, the young just like 
the adult. The Volvox appears to suffer little from the depredations of its ungrateful 
guest. The Proales is lively and energetic in freedom. It glides wildly about, often 
in a zigzag course, turning from side to side, as it dashes rapidly along. Sometimes it 
rotates on its axis as it goes; or, becoming stationary, it turns on its blunt extremity, as 
on a pivot. It is perpetually contracting and elongating, and throwing itself into angular 
folds and contortions.—P.H.G.] 
This is one of the partially loricated Rotifera. The soft front of the head, seen dor- 
sally, is truncate, and much like that of Notops hyptopus. The edge of the trunk, within 
which the head can be withdrawn, is chitinous, and scolloped in regular curves, just like 
the edge of a lorica. At the hind end of the trunk, and on the median line of the dorsal 
' See Phil. Trans. 1855, p. 452, pl. xvii. figs. 27-31. 
